Foundations of houses and other buildings are commonly constructed from construction blocks which are also commonly referred to as cinder blocks. These blocks are manufactured having two hollow cores which extend through the block in a vertical orientation when the blocks are properly stacked. The cores are separated by a cross-member which is located at the midsection of the block.
Anchor bolts secured in a construction block or cinder foundation block wall have long been used to secure or tie the frame of a building or house to the construction block foundation. In the past, the use of such bolts involved inserting a bolt in the space between two abutting construction blocks of the top layer or course of blocks so that the lower end of the bolt rested on the cross-member of the block below with the upper end of the bolt extending above the top layer of blocks. The anchor bolt was permanently secured by pouring cement around the bolt. Once the bolt was cemented in position, the frame of the structure could then be bolted to this upper end.
Although this method worked fairly well for positioning an anchor bolt through only one layer of construction blocks, various problems were still present. For example, because the bolts are randomly positioned by a worker, properly positioning all of the bolts so that their upper ends extend through the centerline of the sill or frame is difficult. Also, it is difficult to position the bolts substantially vertically as required. Finally, because the blocks in such a wall are offset or staggered, the cross-member of the block below the top layer prevented the anchor bolt from being inserted through more than one layer of blocks.
Recent natural disasters including earthquakes, floods, and hurricanes have exposed the inadequacies of the above method of securing an anchor bolt in a construction block wall. In many cases, anchor bolts anchored through only one layer of construction blocks were ripped from their position in the wall. This has caused enactment of ordinances requiring anchor bolts to be secured so that their length travels through at least two layers of a construction block wall. In addition, even when not required by law, builders have been exposed to liability for securing anchor bolts through less than two layers of blocks.
To position an anchor bolt so that it extends through two courses of blocks, it is now common to pass the bolt down through the partially aligned cores of two layers of stacked blocks and subsequently secure the bolt by pouring cement down into the cores. This results in the bolt being secured so that its length travels through the required two layers of blocks.
Because the bolt must be inserted down into small openings through two layers of blocks, it is difficult and time consuming to properly position the bolt in the center of the wall as required. It is also difficult and time consuming to maintain the bolt in its required vertical position while cement is poured into the cores around the bolt. Also, because the cores in the block are somewhat aligned down through the entire height of the wall, there is no base upon which to rest the bottom of the bolt while cement is poured around the bolt. Finally, the fact that the cores are somewhat aligned also results in the waste of a large amount of cement which runs down through the cores below the bolt before filling the desired area around the bolt.
Builders have attempted to solve the above problems by filling the cores below the top two courses with sand, empty bags and other debris to provide some type of base or plug upon which to rest the bottom of the bolt and to prevent a large amount of cement from running down through the entire height of the wall. These attempts at solving the above problems have been unsuccessful and unsatisfactory.
In addition, because cement is poured around the anchor bolt to permanently secure it, building inspectors and others have found it difficult to verify that the anchor bolts do in fact extend down through at least two layers of blocks as required. Unless the inspectors observed the entire process of securing the bolts, the nature of a construction block wall makes it impossible to determine the depth to which the bolts are secured.